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RFID sensor tag and system for small output transducers, and related methods

  • US 9,378,448 B2
  • Filed: 09/14/2014
  • Issued: 06/28/2016
  • Est. Priority Date: 09/22/2013
  • Status: Active Grant
First Claim
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1. Method of passively monitoring a strain exerted on an object, the method comprising:

  • with an antenna provided to an RFID sensor tag, receiving an interrogation signal transmitted by a RFID reader;

    creating a stable supply voltage that is input to a transducer associated with the RFID sensor tag from an induced voltage created as a result of a current induced by the interrogation signal;

    with an RF filter, blocking from the supply voltage a component of voltages created by currents induced in circuit traces by a RF field generated by the RFID reader;

    with the transducer, sensing the strain and outputting a signal on the order of 10'"'"'s of microvolts indicative of the strain while energized by the induced voltage;

    with an amplifier, amplifying the signal from the transducer and filtering RF noise out of the signal to produce a desired signal; and

    transmitting, from the antenna, the desired signal indicative of the strain that is received by the RFID reader.

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